The present disclosure relates to a semiconductor memory device, and more particularly, to voltage generators which generate internal voltages of a specific level even at a low external power supply voltage, and a semiconductor memory device and a memory system which include the voltage generators.
An operating environment of a semiconductor memory device tends to reduce power consumption by using a low operating voltage. The semiconductor memory device may be designed to be driven by an internal voltage which is voltage-dropped from a voltage provided from an external source. With the low power-consumption trend of semiconductor memory devices, the level of an external power supply voltage, which is an operating voltage, is being further lowered. Due to the external power supply voltage of a lowered level, the level of an internal voltage is also further lowered. If the level of the internal voltage is lowered below a target voltage, the operating characteristics of the semiconductor memory device may be deteriorated.